It is our purpose in making this study to determine: 1) the site of the immunologic response to various corneal stimuli such as the injection of foreign proteins or the implantation of xenografted or homografted tissues; 2) the type of the immunologic response at these sites; 3) the onset intensity, and duration of the immunologic response; and ultimately 4) the effect of various therapeutic agents--local, systemic, or both--on this response. The Jerne plaque technique and the migration inhibition test will be employed to make these determinations. The knowledge derived from such a study could have far-reaching effects on the prevention and treatment of corneal immunologic disease processes.